Orchard-heating unit

ABSTRACT

An orchard-heating unit is described having an outer tubular casing and a pulse-type jet combustion chamber and accompanying exhaust tube coaxially mounted therein. The casing has a side opening with an air intake line extending from the side opening to the combustion chamber.

United States Patent Porter et al.

[ Feb. 29, 1972 [54] ORCHARD-HEATING UNIT [72] Inventors: Donald E. Porter, Route 2, Box 213-A; Ray A. Paulus, Route 1, Box 9, both of Prosser, Wash. 99350 [22] Filed: June 8,1970

[21] Appl.No.: 43,994

[52] U.S.Cl. ..l26/59.5,431/1 [51] Int. Cl .A01g 13/06, F23C 3/02 [58] Field ofSearch ..43l/1; 126/595 [56] References Cited UNITED STATES PATENTS Durr et al ..431/l 2,746,529 5/1956 Kamm et a1 ..431/l 2,839,046 6/1958 Kamm ..43l/l X 3,151,454 10/1964 Curtis ..43l/1 X Primary ExaminerCharles J. Myhre AttorneyWells, St. John 8L Roberts [5 7] ABSTRACT An orchard-heating unit is described having an outer tubular casing and a pulse-type jet combustion chamber and accompanying exhaust tube coaxially mounted therein. The casing has a side opening with an air intake line extending from the side opening to the combustion chamber.

3 Claims, 5 Drawing Figures PAIimEmsazs I972 3. 645,250

INVENTORE DONALD E. PORTER RAE A. PAULUJ ORCHARD-HEATING UNIT BACKGROUND OF THE INVENTION This invention relates to orchard-heating units and more particularly to orchard-heating units that utilize the hot gaseous products of a cyclic combustion to heat the air surrounding the orchard.

Even though many different types of orchard-heating units have been devised attempting to replace the traditional utilization of smudge pots and burning of tires, none of them have been widely accepted. The principal reason is that such devices are quite expensive and frequently are quite inefficient in transforming the heat value of the fuel utilized into raising the temperature of the orchard environment. Examples of such devices are disclosed in US. Pat. Nos. 1,311,235; 2,097,544; 2,672,333; 2,960,983; 3,050,l l 1; and 3,055,144.

Of these heating units can be described as burners in which fuel is continuously passed into a burning chamber to maintain a flame to heat air. Several of the devices are designed to create air flows that are directed in confined walls to accelerate and heat the air and then discharge the air from the end to cause convection currents in the orchard to hopefully increase the atmospheric temperature in the orchard. However, it has been found that most of these devices are unable to create the air velocities or to efficiently burn the fuel in such manner as to create high velocity convection currents of sufficient magnitudes to substantially increase the atmospheric temperature.

One of the principal objects of this invention is to provide an orchard heating unit that is capable of efficiently burning fuel in a substantially enclosed chamber to create a substantial pressure and then exhausting the products through a venturi at high velocities parallel with the ground into the surrounding atmosphere to provide substantial convection currents to distribute the heat to efficiently raise the air temperature in the orchard.

An additional object of this invention is to provide an orchard-heating unit that has a fuel and air emission system that is valveless and has no moving parts.

A further object of this invention is to provide an orchardheating unit that is inexpensive to manufacture and operate and which is practically maintenance free.

These and other objects and advantages of this invention will become apparent upon the reading of the following detailed description ofa preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of this invention is illustrated in accompanying drawings, in which:

FIG. 1 is a plan view of a portion of an orchard showing a plurality of orchard heating units positioned thereabout for heating the atmospheric temperature within the orchard;

FIG. 2 is a side view of a single heating unit illustrated in FIG. 1;

FIG. 3 is a longitudinal vertical cross section taken along the line 3-3 in FIG.

FIG. 4 is a transverse cross-sectional view of the heating unit; and

FIG. 5 is a transverse vertical cross section taken along line 5-5 in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in tail to the drawings; FIG. 1 shows an orchard 11 having a plurality of fruit-bearing trees 12 positioned in rows. A plurality of orchard heating units 1 1 are positioned on the ground between some of the trees for heating the atmosphere in the orchard. Such orchard heating units are generally used in the spring of the year to raise the temperature sufficiently to prevent frost damage to the fruit buds that are beginning to blossom.

Each of the orchard-heating units 11 has a tubular outer casing 14 (FIG. 2) with an open upstream end' 15 and open downstream end 16. A side aperture 17 is formed through the tubular casing along the upper profile of the tubular casing near the open upstream end 15. The tubular casing 14 is mounted on leg stands 18 and 20 to generally orient the orchard heating unit in a substantially horizontal position. The front leg stand 20 includes a single leg element 22. The back leg stand 18 includes two leg elements 23 and 24 that are fixed to the lower profile of the tubular casing. The leg elements 23, 24 extend downwardly, toward the upstream end 15. A cross brace 25 extends between the leg elements 23, 24 providing substantial rigidity.

Each orchard-heating unit 1 1 includes a pulse-type jet combustion chamber 26 that has an enclosed end 27 and an open end 28. The open end 28 has a reduced section 30 that is connected to an exhaust tube 31 to form a venturi. The combustion chamber 26 and the exhaust tube 31 are mounted substantially coaxially within the tubular casing 14 by thin spacers 33. An annular space 35 is formed between the tubular casing and the combustion chamber and exhaust tube from the upstream end 15 to the downstream end 16.

A fuel line 37 is attached to a pressurized storage tank 38 and extends through the open upstream end 15 of the casing and into the interior of the combustion chamber 26 to supply fuel to the combustion chamber. A metering orifice 39 is mounted in the fuel line 37 for regulating the fuel flow. An igniter 40 is mounted in the combustion chamber for initially igniting the fuel and air mixture. The igniter may be in the form of a spark plug. Once the fuel is ignited, combustion will maintain itself without any requirement for further use of the igniter. The igniter 40 is only used during the startup of the heating unit.

An air intake line 42 extends into the interior of the combustion chamber 26 at point 43. The air intake line extends from the combustion chamber outwardly into the annular space 35 and makes a bend 44. The outer end of the line 42 has a longitudinal section 45 that extends substantially parallel to the axis of the orchard-heating unit, terminating at point 46 adjacent the side perture 17. It should be particularly noted that the air intake line 42 is directed downstream confined within the tubular casing so that any flame or exhaust emitted from the air intake line 42 is directed toward the downstream end 16.

During the operation of the orchard heating unit, fuel is generally fed to the combustion chamber 26 under a constant pressure. Initially a voltage source is connected to the igniter to generate a spark within the combustion chamber to ignite the fuel and air mixture. The air is taken in through the air intake line 42 from the annular space 35 and through the side aperture 17. The combustion within the substantially enclosed combustion chamber 26 create a rapid increase in pressure, resulting in the combustion products being forced out through the exhaust tube 31 and the air intake line 42. As the combustion products move through the venturi, the exhaust products are accelerated to exhaust the products from the exhaust tube at very high velocities. This causes a vacuum in the annular space 35 adjacent the end 16 to draw air through the upstream end 15. The combustion chamber and exhaust tube are heated to in turn heat the air that flows through the annular space 35.

Near the end of the combustion and exhaust cycle a vacuum is created within the combustion chamber 26, causing some of the hot combustion products to move back into the combustion chamber and to draw fresh air through the air intake line 42 into the combustion chamber. When a vacuum is created within the combustion chamber additional fuel is sucked into the combustion chamber providing a second combustible mixture. At this point, a second explosion takes place providing for a rapid increase in pressure in the combustion chamber which again causes the product gases to be accelerated outward through the exhaust tube. This cyclic combustion phenomenon can be maintained on a continuous cyclic basis without any need for a spark to be provided by the igniter. After initial combustion in the confined, but vented volume, produces a rapid pressure rise and rapid discharge of gases. As previously mentioned, the pressure in the reaction or combustion chamber will ultimately fall below atmospheric pressure and a return flow to the chamber will subsequently occur. Thus, a self-sustaining pulsating combustion will result.

It should be noted that such a unit creates substantially higher velocity of exhaust gases and efficiently burns the fuel to provide sufficient means for producing relatively high velocity convection currents to heat the atmosphere in the orchard. It further has a high heat release per unit volume capability which is very important. With this unit, there is no it need to have a mechanical blower. The simplicity of the engine is remarkable.

It should also be noted that the outer tubular casing enables air to flow from the upstream end to the downstream end and being heated in the process to provide additional heat content to the environment. Also there is no valve in the fuel or air intake system. it has also been found that such a unit can operate on various types of fuel, including propane, gasoline, stove oil, and diesel.

It should be further noted that the termination 45 of the air intake line 42 is directed toward the exhaust end 16 so that any gaseous combustion products that flow out the air intake line 42 are directed within the tubular casing to be combined with the other gaseous exhaust products.

A very significant advantage of this unit is that it is practically pollution free. The fuel is burned almost completely, producing no smoke or odor. This is in marked contrastto the typical burner-type orchard-heating units.

As various changes can be made in the form, construction and arrangements of parts herein without departing from the sphere and scope of this invention and without sacrificing any of its advantages, it is to be understood the above described embodiment is to be interpreted as illustrative and not to limit the scope of this invention. Only the following claims are intended to define this invention.

What is claimed is:

1. An orchard-heating unit:

a tubular outer casing having an open upstream end and an open downstream end;

leg elements afiixed to the tubular casing for supporting the tubular casing above the ground in a substantial horizontal orientation;

a substantially enclosed pulse jet combustion chamber having an exhaust tube extending therefrom in which the combustion chamber and the exhaust tube are mounted substantially coaxially within the outer casing with an annular space therebetween to permit a stream of air to flow through the tubular casing from the upstream end to the downstream end about the combustion chamber and the exhaust tube;

a fuel line extending into the interior combustion chamber to supply fuel thereto upon demand;

an air inlet line extending from the annular space to the interior of the combustion chamber to supply air upon demand; and

an igniter extending into the interior of the combustion chamber to initially ignite the fuel and air to start a continuous pulsating combustion and exhaust of the fuel and air mixture in the combustion chamber;

said outer casing including a side intake aperture formed therein;

said air inlet line extending from the combustion chamber upstream of the side intake aperture and then directed downstream terminating adjacent the side intake aperture to draw air through the side intake aperture into the combustion chamber and to exhaust part of the combustion products into the annular space toward the downstream end to add said part of combustion products to the combustion products leaving the exhaust tube.

2. The orchard-heating unit as defined in claim 1 wherein the air intake is directed downstream substantially parallel with the axis of the tubular casing.

3. The orchard-heating unit as defined in claim 1 wherein the air intake line is confined totally within the tubular casing. 

1. An orchard-heating unit: a tubular outer casing having an open upstream end and an open downstream end; leg elements affixed to the tubular casing for supporting the tubular casing above the ground in a substantial horizontal orientation; a substantially enclosed pulse jet combustion chamber having an exhaust tube extending therefrom in which the combustion chamber and the exhaust tube are mounted substantially coaxially within the outer casing with an annular space therebetween to permit a stream of air to flow through the tubular casing from the upstream end to the downstream end about the combustion chamber and the exhaust tube; a fuel line extending into the interior combustion chamber to supply fuel thereto upon demand; an air inlet line extending from the annular space to the interior of the combustion chamber to supply air upon demand; and an igniter extending into the interior of the combustion chamber to initially ignite the fuel and air to start a continuous pulsating combustion and exhaust of the fuel and air mixture in the combustion chamber; said outer casing including a side intake aperture formed therein; said air inleT line extending from the combustion chamber upstream of the side intake aperture and then directed downstream terminating adjacent the side intake aperture to draw air through the side intake aperture into the combustion chamber and to exhaust part of the combustion products into the annular space toward the downstream end to add said part of combustion products to the combustion products leaving the exhaust tube.
 2. The orchard-heating unit as defined in claim 1 wherein the air intake is directed downstream substantially parallel with the axis of the tubular casing.
 3. The orchard-heating unit as defined in claim 1 wherein the air intake line is confined totally within the tubular casing. 